Connecting members of this type have already been proposed in which the hoop consisted of a wire ring severed at one point, which was threaded through a hole and pressed with its two open ends on the two arms of the connecting member. A sprung hoop of this type has the advantage over a self-clamping connecting member, that it can be made of a very springy material which is not to be subjected to any demands with respect to conductivity. The proposed sprung hoop does, however, increase the size of the plug connection and is difficult to fit. In addition, its effectiveness is limited.